Lifting jack



March 17. 1925.

J. G. PICKERING, JR

LIFTING JACK 2 3 Sheets-Sheet 1 Filed Oct.

March 17. 1925. I 1,529,963

J. G. PICKERING. JR

LIFTING JACK Filed Oct. 2. 1924 3 Sheets-Sheet 2 \R JGEPic keri g March-1 7. i 925.

J. G. PICKERING, JR

LIFIING JACK Filed Oct. 2. 1924 3 Sheets-Sheet 5 t]: G..Pic7i'eriPatented Mar. '17, 1925.

UNITED STATES PATENT OFFICE.

tenses JESSE GERALDUS IIGKEB-ING, J 13., OFNASHVILLE, TENNESSEE. 1 I

LIFTINGr JACK.

Application filed October .2, 1924. Serial No. 741,227.

To all whom it may concern Be it known that 1, Jesse Gnnnnoos Pronnnnve,Jr., a citizen of the United States, residing at Nashville, in thecounty of David son and State of Tennessee, have invented certain newand useful Improvements in Lifting Jacks, of which the following is aspecification.

This invention relates to lifting jacks, and more particularly to aconstruction adapted for use as asingle or double acting jack and whichhas the advantage of quickly elevating the object to be lifted, or onthe other hand quickly lowering the same.

One of the objects of the invention is to provide a simple and practicalconstruction that may be readily collapsed into compact form, and yet isextensible to a maximum distance when desired or required, therebymaterially increasingits range of use. In that connection itis alsoproposed to provide a construction that is dust proof and easy tooperate.

A further object of the invention is to provide a jack having means forengaging objects to be lifted at various heights in a convenient andpractical manner.

A still further object of the invention is toprovide a novel arrangementof lifting and sustaining pawls which makes the jack fulfill therequirements of either-a single or double acting jack.

Vith the above and other objects in view which will more readily appearas the nature of'the invention is better understood, the same consistsin the novel construction, combination and arrangement of partshereinafter more fully described, illustrated and claimed.

A preferred and practical embodiment of the invention is shown in theaccompanying drawings, in which:

Figure 1 is a view illustrating the jack in I use, the rack bars thereofbeing manipulated into elevated positions.

Figure 2 is a detail side elevation of the jack collapsed.

Figure 3 is an enlarged vertical sectional view of the jack with theparts as in Figure 2. 1 K

Figure 4. is ahorizontal sectional view taken on the line it-a of Figure3.

Figure 5 is a vew similar to Figure 3 showing the lifting pawls at theupward limit of their lifting movement.

Figure 6 is a view similar to Figures 3 and 5 illustrating the relativeposition of the lifting pawls and sustaining pawls during the descent ofthe jack.

Figure 7 is a detail horizontal sectional view taken on the line 77 ofFigure 2.

Figure 8 is a detail perspective view of the adjustable lifting lug.

Similar reference characters designate corresponding parts throughoutthe several figures of the drawings.

The invention in its general organization includes a casing designatedgenerally as A which serves both as a housing for the rack bars Band C,as well as an intermediate member of the ack as clearly shown inFigurel.

The rack bar B is provided with a base 01' foot portion D while the rackbar C is provided with a lifting horn E, the said base D and horn Ebeing offset from their respec tive rack bars'in opposite directions,and the rack bars each being providedwith grooves G for engaging withthe ribs It of the casing A and its cover A (see Fig. 4). Thisarrangement permits the rack bars to be slidably guided in the oppositesides of the casing A in'a stable and practical manner thereby toprovide a rigid structure for distributing the load sustained by theack.

One of the novel features of the invention resides in the provision ofan adjustable supporting lug F which is bifurcated at F in Figure 8 andthereby adapted to straddle the casing A and its cover A as shown inFigures 1. andv 2, whereby, in cooperation with the shoulders F in oneedge of the casing and the lugs F on thesides thereof, the said lug' Fwill be held in any desired adjusted position atone edge of the casing.To prevent accidental longitudinal displacement of the lugs F, theabutments F may be provided with the ribs F which cooperate with therecesses F of the lugs as shown in Figures 1. and 2, thereby serving toprevent the lateral slipping of the lugs while the jack is beingmanipulated to lift the load. i

Referring to Figure 1, and assuming the rack bar 13 to be relativelystationary, the

casing A and rack bar C may be moved relative to the said rack bar Bwhen the handle H of the novel elevating means M (Fig. 2) employedherein is actuated. This elevating means preferably consists ofanactuator 1 3) comprising a body formed with opposite bearing portions2 and 3 respectively journaled in the sidewall of the casing A and thecover A. as shown in Figure 1, and having the oppositely extendingbifurcated wings 4 l. The said wings have pivotallytitted therein, theoppositely extending lifting pawls 55 whose free ends 6 are adapted toengage respectively with the rack bars 13 and C while the intermediateportions thereof are engaged by the springs 7 thereby normally to forcethe said ends 6 of the lifting pawls into engagement with the reverselyarranged shoulders of the racks. The bearing portion 2 is. provided witha squared or angular lug 2 for receiving a corresponding opening of thehandle H, and it will. therefore, be apparent that when the actuator 1is rocked by the manipulation of the handle H the lifting pawls 55 willbe alternately moved in opposite directions thereby lifting the casing Aand the upper rack C. I

For the purpose of retaining the casing and rack C in the positions towhich they are elevated by the manipulation of the lift ing pawls 55,the sustaining pawls 8-8 are provided, the same being pivoted as shownat 9 to the side wall of the casing A.

These sustaining pawls Te -8, are adapted to be normally pressed intoward the shouldered edges of the racks. but when it is desired tocollapse the. jack, that is, permit the casing A and upper rack bar Cto. descend. it is necessary that the sustaining pawls be temporarilyheld out of the path of the shouldered racks, and to that end, eachsustaining pawl is provided with a manually set controlling device whicheither places the pawl under compression or ten sion, according towhether the jack is to perform lifting or lowering service. Aswill beseen from the drawings this means preterably consists of a spindlemember 10 which carries therewith a spring S con'iprising a radiallyprojecting portion 11 looped asindicated at 12 and continued to form acoiled portion 13 adapted to engage with the intermediate part of anadjacent pawl 5 to counteract the force of its spring 7 while the loop.12 also receives one end of a looped tensioning and compression spring14 whose free end 15 is eccentrically connected to the sustaining pawl8.

When it is desired to manipulate the jack to. elevate an object, thethumb-grips 16 carried by the projecting pins of the spindle 10 are setin the full line position shown in Figures 1 and 2, and in this positionthe looped parts 1 1' are placed under compression thereby to force thefree ends 8 of the sustaining pawls into the teeth or shoulders of therack bars so that upon eachreciprocation of the actuator 1 the lowerlifting pawl will cause the member A to move upwardly and therebyelevate the lower sustaining pawl 8 to the next tooth. above, andin-turn the upper lifting pawl will elevate the rack bar 0 so that theupper sustaining pawl 8 will engage the next tooth or shoulder below onthe rack O. To prevent the lifting pawls 5 from overreaching in theirmovement the top and bottom walls of the casing A are provided. withguiding portions 6.

hen it is desired to permit the jack to collapse and lower the object,the thumbgriips 16 are shifted to the substantially vertical positionsshown by dotted lines in Figure 1 thereby having the effect of placingthe sustainingpawls 8-8 under the tension of the looped springs 14. andthrusting the 80 coiled part 18 into engagement with the lifting pawls 5to temporarily push the lifting pawls out of engagement with theshoulders while the sustaining pawls are holding or supporting the load.In other words the spring 13 will push the pawls 5 baelnvardly after theload is shifted from 5 to S, and in the lowering process the ends 8* ofthe pawls are not in contact with the shoulders of the rack until thesame are forced into that position by the descent of the pawls In thatconnection it may be pointed out that the operation of the lifting pawls5 and sustaining pawls 8 are substantially the same as disclosed inmycopending application Serial No. 71027, filed May 1, 1924:.

As will be observed from Figure 7. the thumb-grip levers 16 are providedwith spring pressed catch members 17 whichcooperate with the raisedabutment segments 18 thereby to hold the said levers in the desired. setpositions 90 apart.

As previously indicated this ack can be used as a single or doubleacting jack. That is, either the rack B or the rack C can be operated.independently of the other by the proper manipulation of the thumb-grips16. For example, if it is desiredto lift an object from the ground bythe use of the lifting lug l and it is not desired to elevate the rack Cto avoidinterference with a superposed object, it is only necessary toplace the thumb-grip 16 for the rack G in the dotted line'positionshownin Figure 1. leaving the other thumb-grip for the rack B in thefull line position shown. Tn that way the manipulation of the actuator 1will not cause the lifting of the rack C and will per- -mit the same toremain stationary.

Therefore, it will be understood that either or both of the rack bars Band C may be operatech according to the position in which the springs Sare set by the manipulation of the thumb-grip levers 16. By selectivelycont-rolling or setting the springs S inthe desired position. it will bereadily apparent that either a single or double acting jack is readilyprovided.

From the foregoing, it will be apparent that the present inventionincludes a simple and practical organization of parts which provide alifting jack con'iprising a pair of rack bars relatively movable to eachother and having reversely shouldered bases, the said rack bars beinginterlocked with the casing or housing and having novel lifting and.sustaining means for holding an objectelevated or 'ioi'mitting it todescend as desired.

I claim j 1. A lifting ack including a casing, rack bars fitted withinopposite ends of said casing and adjustable in opposite directions, arockable actuator journalcd in the opposite side walls of the casing,sustaining pawls carried by the inside of the casing, and adapted toengage the rack bars, and lift ing pawls pivotally carried by therockable actuator and disposed in opposite directions between the rackbars and engaging therewith.

2. A lifting jack including a casing, rack bars fitted within oppositeends of the casing and projecting therefrom, a bearing foot carried bythe rack bar projecting from the bottom of the casing and a lifting horncarried by the rack bar projecting from the top of the casing,sustaining pawls pivoted to the inside of the casing, an actuator havingan exterior operating connection journaled in the opposite side walls ofthe casing, and lifting pawls pivot-ally carried by said aotuator andhoused within the casing and en gaging the pawls of the rack bars alsoconcealed within the casing.

8. A lifting jack including a casing, rack bars fitted within oppositeends of the casing and adjustable in opposite directions, a rockableactuator journaled in the opposite side walls of the casing andconsisting of a bearing portion and opposite bifurcated por tions,spring-pressed rack engaging lifting pawls pivoted in said bifurcatedportion, and sustaining pawls carried by the inside of the casing.

4. A lifting jack including a casing, rack bars fitted within oppositeends of said cas ing and adjustable in opposite directions, an

actuator including a rockable pivot member said pivot member, rackengaging sustainmeans arranged within the casing for controlling theoperation of said sustaining pawls and the corresponding lifting pawls,and means for controlling said spring means comprising a shifter membermounted in the side wall of the casing and having an exteriorly arrangedfinger engaging portion.

5. A lifting jack including a casing, rack bars slidably fitted inopposite ends of the casing, an actuator pivoted within the easingbetween the rack bars and having an opcrating-lever engaging portionprojecting eXteriorly of the casing, lifting pawls pivotally carried bythe rockable actuator and disposed in opposite direction between therack bars to engage therewith and sustaining pawls carried by the insidewall of the casing for engaging with the racks, and controlling devicesfor said sustaining pawls, said devices comprising double looped springseccentrically connected with said pawls and a pivot member journaled inthe side wall of the casing for carrying and manipulating said springs,and thumb levers carried by said pivot members and mounted on theoutside of the casing.

6. A lifting jack including a casing, rack bars slidably fitted withinopposite ends of the casing, a rockable actuator pivoted in oppositeside walls of the casing between the rack bars, lifting pawls carried bythe actuator, sustaining pawls carried by the casing, and means forsimultaneously controlling a sustaining pawl and corresponding liftingpawl, said means comprising a pivot member journaled in the side wall ofthe casing and having an exterior finger engaging portion and a springcarried by the inner end of said pivot member and directly connectedwith the sustainingpawl at one end and having anotherend slidablyengaging with the lifting pawl corresponding to said sustaining pawl.

In testimony whereof I hereunto affix my signature in the presence oftwo witnesses.

' JESSE GERALDUS PICKERING, Jr. Witnesses:

TRULA MATHIS, J. G. AMIS.

